1. Field of the Invention
The present invention relates to a zoom lens and an image pickup apparatus equipped with a zoom lens.
2. Description of the Related Art
In recent years, reduction in the size, weight, and manufacturing cost of cameras using an electronic image pickup element, such as digital cameras, have been needed. To achieve reduction in the size, weight, and manufacturing cost of such cameras, it is necessary to reduce the size of the camera body and the optical system.
On the other hand, there are needs for wide-angle shooting such as the shooting of a large structure or building or the taking of a souvenir photograph in an extensive background. In addition, people wish to take wide-angle photographs and telephoto photographs using only one lens. As lenses that meet such needs in shooting, wide angle zoom lenses having a half angle of view larger than 37 degrees and a zoom ratio higher than 4.5 provide a convenient view angle range, enabling shooting in wide variety of situations.
As a lens configuration that can achieve a relatively wide angle of view and high zoom ratio, a zoom lens including, in order from the object side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit having a positive refractive power, a fourth lens unit having a negative refractive power, and a fifth lens unit having a positive refractive power has been known, as disclosed in Japanese Patent Application Laid-Open Nos. 2010-191199 and 2003-287681.